In LTE (Long Term Evolution), specifications of which have been designed in 3GPP (3rd Generation Partnership Project) which is a project aiming to standardize a mobile communication system, a user terminal in an idle state performs a cell reselection on the basis of neighboring cell information broadcast periodically from a serving cell.
The neighboring cell information is a system information block type 4 (SIB4) to a system information block type 8 (SIB8), for example. The SIB4 is information on a neighboring cell within a frequency (Intra-frequency). The SIB5 is information on a neighboring cell of another frequency (Inter-frequency). The SIB6 to the SIB8 are information on a neighboring cell having a standard different from the LTE (E-UTRA).
Further, in recent years, attention is paid to a technology of increasing a communication capacity by arranging a small cell within a macro cell. The small cell is a pico cell or a femto cell, for example. The small cell belongs to the same frequency as the macro cell or a frequency different therefrom. Further, the small cell may comply with a standard different from that of the LTE (E-UTRA).
However, there is a problem that when a large number of small cells are arranged within a macro cell, an amount of neighboring cell information that should be broadcast by the macro cell increases and overhead caused along with the broadcasting of the neighboring cell information increases.